Steerable catheter with pull wire

ABSTRACT

In one representative embodiment, a steerable catheter device comprises a shaft comprising a proximal portion, a distal portion, and a pull-wire lumen that extends at least partially through the proximal and distal portions. A pull wire extends through the pull-wire lumen and has a proximal end portion and a distal end portion, wherein the distal end portion of pull wire is fixed to the distal end portion of the shaft. An adjustment mechanism is operatively connected to the proximal end portion of the pull wire and configured to increase and decrease tension in the pull wire to adjust the curvature of the distal portion of the shaft. An axially non-compressible pull-wire sleeve extends co-axially through the pull-wire lumen and over the pull wire.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 62/088,449, filed Dec. 5, 2014, which is incorporatedherein by reference.

FIELD

The present application pertains to embodiments of steerableendovascular delivery devices.

BACKGROUND

Endovascular delivery devices are used in various procedures to deliverprosthetic medical devices or instruments to locations inside the bodythat are not readily accessible by surgery or where access withoutsurgery is desirable. Access to a target location inside the body can beachieved by inserting and guiding the delivery device through a pathwayor lumen in the body, including, but not limited to, a blood vessel, anesophagus, a trachea, any portion of the gastrointestinal tract, alymphatic vessel, to name a few. In one specific example, a prostheticheart valve can be mounted in a crimped state on the distal end of adelivery device and advanced through the patient's vasculature (e.g.,through a femoral artery and the aorta) until the prosthetic valvereaches the implantation site in the heart. The prosthetic valve is thenexpanded to its functional size such as by inflating a balloon on whichthe prosthetic valve is mounted, or by deploying the prosthetic valvefrom a sheath of the delivery device so that the prosthetic valve canself-expand to its functional size.

The usefulness of delivery devices is largely limited by the ability ofthe device to successfully navigate through small vessels and aroundtight bends in the vasculature, such as around the aortic arch. Varioustechniques have been employed to adjust the curvature of a section of adelivery device to help “steer” the valve through bends in thevasculature. Typically, a delivery device employs a pull wire having adistal end fixedly secured to the steerable section and a proximal endoperatively connected to an adjustment knob located on a handle of thedelivery device outside the body. The pull wire is typically disposed ina pull-wire lumen that extends longitudinally in or adjacent to a wallof the delivery device, for example, a sheath or catheter. Adjusting theadjustment knob, for example, rotating the knob, applies a pulling forceon the pull wire, which in turn causes the steerable section to bend.

A drawback of this design is that the delivery device suffers from aphenomenon known as “whipping” when the device is torqued or rotatedrelative to its central longitudinal axis, for example to adjust therotational position of the distal end portion of the delivery device,while the delivery device is disposed in a curved anatomical pathway,for example, a blood vessel, while the steerable section is deflected tomatch the curvature of the anatomical pathway. In the deflectedconfiguration, the pull wire and pull-wire lumen adopt a low-energyconfiguration along an inside of the curved section of the deliverydevice. The deflected portion of the delivery device resists rotationaround the longitudinal axis because such rotation would move the pullwire away from the inside of the curve. In many cases, this resistancemakes rotation impossible as a practical matter. “Whipping” occurs whenthe user successfully rotates the delivery device: as the handle isrotated, the curved section initially resists, then, as the usercontinues to rotate the handle, suddenly rotates a full 360° from theinitial low-energy configuration to a final (equivalent) low energyconfiguration. Some prior art devices utilize multiple pull wires ortensioning members to effect positioning of the steerable section inmore than one flexing plane relative to the central axis of the device;however, these devices are complicated, and like single pull-wiredevices, suffer from “whipping” when rotated. Thus, a need exists for adelivery device with improved torqueability and steerability.

SUMMARY

Disclosed herein are steerable catheter devices and related methods,which can be used to deliver a medical device, tools, agents, or othertherapy to a location within a body of a subject. In someimplementations, the steerable catheter devices can be used to deliver amedical device through the vasculature, such as to a heart of thesubject. These devices may comprise one or more eccentrically positionedpull wires configured to cause a shaft to curve in a given direction,and/or to cause the shaft to straighten. The disclosed devices canfurther comprise a flexible, axially non-compressible pull-wire sleevethat extends co-axially over at least a portion of the pull wire, withthe pull-wire sleeve free-floating within a pull-wire lumen. Thepull-wire sleeve is effective to reduce or eliminate disequilibriumcaused by torqueing the shaft while in a contoured configuration andunder the pulling force of the pull wire, thereby enhancing thesteerability and torqueability of the catheter device.

In one representative embodiment, a steerable catheter device comprisesa shaft comprising a proximal portion, a distal portion, and a pull-wirelumen that extends at least partially through the proximal and distalportions. A pull wire extends through the pull-wire lumen and has aproximal end portion and a distal end portion, wherein the distal endportion of pull wire is fixed to the distal portion of the shaft. Anadjustment mechanism is operatively connected to the proximal endportion of the pull wire and configured to increase and decrease tensionin the pull wire to adjust the curvature of the distal portion of theshaft. An axially non-compressible pull-wire sleeve extends co-axiallythrough the pull-wire lumen and over the pull wire.

In another representative embodiment, a method comprises providing acatheter device having a shaft, a pull wire extending through the shaft,and an axially non-compressible pull-wire sleeve. The pull wire extendsat least partially through the pull-wire sleeve, the pull wire and thepull-wire sleeve are radially offset from a central axis of the shaft,and the shaft comprises a proximal portion and a distal portion. Themethod further comprises inserting the catheter device into the body ofa patient and applying tension to the pull wire to adjust the curvatureof the distal portion of the shaft.

In another representative embodiment, a steerable catheter devicecomprises a shaft having a proximal portion and a distal portion, andfirst and second pull wires. The first and second pull wires haverespective proximal portions and respective distal portions. Theproximal portions of the first and second pull wires extend through theproximal portion of the shaft in close proximity to each other. Thedistal end portions of the first and second pull wires extend throughthe distal portion of the shaft in close proximity to each other over afirst distance defining a primary flexing section, diverge away fromeach other over a second distance, and then extend parallel to eachother at angularly spaced locations over a third distance defining asecondary flexing section. Tension applied to the first pull wire and/orthe second pull wire is effective to flex the distal portion away fromthe central axis of the shaft, wherein the direction of flexion isdetermined by the relative tensions in the pull wires.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a catheter device, according to one embodiment.

FIG. 1A is an enlarged view of a portion of the catheter device of FIG.1, showing the connection of a pull-wire sleeve to a stop member.

FIG. 2A is a side view of a catheter device of FIG. 1 shown with acurved outer shaft and with a steerable distal tip portion of an innershaft curling inwards in the same plane (x-y plane) as a curved outershaft of the assembly.

FIG. 2B is a side view of the catheter device of FIG. 2A, with a distaltip portion of an inner shaft of the assembly extending in a directionorthogonal to the plane of the outer shaft (into the page as shown).

FIG. 2C is a side view of the catheter device of FIG. 2A, with a distaltip portion of an inner shaft of the assembly flexing in an oppositedirection from the outer shaft but in the same plane (x-y plane) as theouter shaft.

FIG. 2D is side view of the catheter device of FIG. 2A, with a distaltip portion of an inner shaft of the assembly extending in a directionorthogonal to the plane of the outer shaft (out of the page as shown).

FIG. 3 is a longitudinal cross-sectional view of the catheter device ofFIG. 1.

FIG. 4 is a cross-sectional view of the catheter device of FIG. 1, takenalong line 4-4 of FIG. 3.

FIG. 5 is another cross-sectional view of the catheter device of FIG. 1,taken along line 5-5 of FIG. 3.

FIG. 6 is a schematic side view of a distal end portion of a catheterdevice, according to another embodiment, having two pull wires whichextend through a central proximal lumen and two distal lumens.

FIG. 7 is a cross-sectional view of the catheter device of FIG. 6, takenalong line 7-7 of FIG. 6.

FIG. 8 is a perspective view of the catheter device of FIG. 6, showingthe ability of the distal tip portion to flex at various angles within arange of flexion (a) of the distal tip portion.

FIG. 9 is a schematic side view of a catheter device comprising two pullwires, according to another embodiment.

FIG. 10 is a cross-sectional view of the catheter device of FIG. 9,taken along line 10-10 of FIG. 9.

FIG. 11 is a flattened view of the catheter device of FIG. 9 with thecatheter wall opened along a line opposite the main pull-wire lumen.

FIG. 12 is a flattened view of another embodiment of a catheter device.

FIG. 13 is a transverse cross section of the catheter device of FIG. 12.

DETAILED DESCRIPTION

Disclosed herein are steerable catheter devices and related methods,which can be used to deliver a medical device, tools, agents, or othertherapy to a location within the body of a subject. Examples ofprocedures in which the steerable catheters are useful includeneurological, urological, gynecological, fertility (e.g., in vitrofertilization, artificial insemination), laparoscopic, arthroscopic,transesophageal, transvaginal, transvesical, transrectal, and proceduresincluding access in any body duct or cavity. Particular examples includeplacing implants, including stents, grafts, embolic coils, and the like;positioning imaging devices and/or components thereof, includingultrasound transducers; and positioning energy sources, for example, forperforming lithotripsy, RF sources, ultrasound emitters, electromagneticsources, laser sources, thermal sources, and the like. In someembodiments, the steerable catheter device is a steerable ballooncatheter, comprising one or more balloons at or near a distal endportion thereof. In some implementations, the steerable catheter devicescan be used to deliver a medical device through the vasculature, such asto a heart of the subject. These devices may comprise one or moreeccentrically positioned pull wires configured to cause a shaft to curvein a given direction, or to straighten. The disclosed devices canfurther comprise a flexible, axially non-compressible pull-wire sleevethat extends co-axially over at least a portion of the pull wire and isfree-floating within a pull-wire lumen. The pull-wire sleeve effectivelyreduces or eliminates disequilibrium caused by torqueing the shaft whilein a contoured configuration and under the pulling force of the pullwire, thereby enhancing the steerability and torqueability of thecatheter device.

Exemplary Embodiments

Referring to FIG. 1, a catheter device 10, according to one embodiment,comprises a handle portion 12 and a shaft 14 extending distallytherefrom. The shaft 14 comprises a proximal portion 18 and a distalportion 20. The curvature of the distal portion 20 of the shaft 14 canbe controlled by a pull wire 22. As best shown in FIG. 3, the pull wire22 extends through a peripheral pull-wire lumen 34 formed in a side wallof the shaft 14, and has a proximal end portion 42 operatively connectedto an adjustment mechanism 26 in the form of a rotatable knob mounted onthe handle 12. The adjustment mechanism 26 is configured to increase anddecrease tension in the pull wire to adjust the curvature of the distalportion 20 of the shaft 14, as further described below. The distalportion 20 of the shaft can be constructed from a relatively moreflexible material than the proximal portion 18 or otherwise can beconstructed to be relatively more flexible than the proximal portion 20such that the curvature of the proximal portion can remain substantiallyunchanged when the curvature of the distal portion is adjusted byapplying tension thereto by the pull wire, as further described below.Further details of the construction of the shaft, the handle and theadjustment mechanism are described in U.S. Patent ApplicationPublication Nos. 2013/0030519, 2009/0281619, 2008/0065011, and2007/0005131, which are incorporated herein by reference in theirentireties.

The catheter device 10 can further comprise a flexible, axiallynon-compressible pull-wire sleeve 28 extending co-axially over at leasta portion of the length of the pull wire 22. In the illustratedembodiment, the pull-wire sleeve 28 comprises a helical coil, whichdesirably is a closed pitch coil without spacing between adjacent turnsof the coil to avoid axial compression of the coil. The coil can be madeof any suitable biocompatible metal (e.g., stainless steel, nitinol,etc.), polymer, or combination thereof. In alternative embodiments, thepull-wire sleeve 28 can have other configurations that are sufficientlyflexible yet substantially axially non-compressible. For example, thepull-wire sleeve can comprise an elongated slotted tube (e.g., a metaltube) that has a plurality of axially-spaced, circumferentiallyextending slots formed (such as by laser cutting) along the length ofthe tube. In another example, the pull-wire sleeve 28 can comprise apolymeric tube reinforced with a braided metal layer, such as polyimidetube reinforced with a braided stainless steel layer. In this example,an inner polymeric layer can be secured to the inner surface of thebraided layer and/or an outer polymeric layer can be secured to theouter surface of the braided layer.

Referring to FIGS. 1 and 3, the coil 28 extends through the pull-wirelumen 34 for the majority of the length of the shaft and proximate thehandle 12, the coil extends outside the shaft 14 through an opening 50in the proximal portion 18 of the shaft and terminates at a stop member24 mounted on the shaft adjacent the handle. A length of the coil 28extending outside of the shaft 14 is shown as Li in FIG. 1. The proximalend of the coil 28 can be fixed to the stop member 24, such asmechanically, by press-fitting, by threads, by swaging, by crimping, byclamping, by welding, or using a suitable adhesive. As shown in FIG. 1A,the proximal end of the coil 28 can extend into a bore 58 in the stopmember 24, where the coil can be secured in place, as discussed above.In various other embodiments, the coil 28 can originate more proximally(proximal to the stop member 24), such as at the handle portion 12, ormore distally (distal to the stop member 24).

As shown in FIG. 3, a distal end portion 40 of the pull wire 22 can befixed relative to the shaft 14 proximate of the distal, terminal end 36of the shaft. For example, the distal end portion 40 of the pull wire 22can be fixed to a ring 38 that is embedded or otherwise secured to theshaft at or adjacent to the distal opening of the pull-wire lumen 34. Asshown in FIGS. 1 and 1A, a proximal end portion 42 of the pull wire 22extends through the stop member 24 and into the handle 12 where it isoperative connected to the adjustment knob 26. For example, the proximalend portion 42 of the pull wire can be secured to a slidable nut (notshown) inside the handle which is configured to apply and releasetension on the pull wire upon rotation of the knob 26.

When tension is applied to the pull wire 22, side wall areas of thedistal portion 20 of the shaft in proximity to the pull wire 22 arecompressed, while side wall areas on the opposite side aretensed/stretched, thereby causing flexion of the distal portion 20 inthe direction of the pull wire 22 (relative to a central axis of thedistal end portion 20) (as shown in FIG. 1 and in phantom in FIG. 3).The adjustment knob 26 located on the handle 12 can be turned in onedirection to apply tension to the pull wire 22, and can be turned in theopposite direction to release tension thereupon. In some embodiments,the knob 26 is turned clockwise to apply tension, while in otherembodiments, counter-clockwise rotation applies the tension. In anycase, when tension in the pull wire is decreased or released, theresiliency of the distal portion 20 of the shaft causes the distalportion to return to its non-flexed configuration. In its non-flexedconfiguration (in the absence of pull-wire forces), the distal portion20 can be substantially straight (as shown in FIG. 3) or can be curved.

In alternative embodiments, the distal portion 20 can be curved when itis in its non-flexed configuration, and application of tension by thepull wire causes the distal portion 20 to straighten while release oftension allows the distal portion to return to its pre-curved,non-flexed configuration. In such embodiments, the pull wire 22 extendsthrough a pull-wire lumen that is offset from the central axis of theshaft toward the outer, convex curved portion of the shaft such that thepull wire applies a tensile force to the inner, concave curved portionof the shaft and a compressive force to the outer, convex curved portionof the shaft. In other embodiments, the pull-wire lumen extendslongitudinally at a location other than the inside or outside of apre-curved catheter.

As shown in FIGS. 3-5, the shaft 14 can comprise a central lumen 32 thatextends the length of the shaft. The central lumen 32, the diameter ofwhich can be significantly larger than the diameter of the pull-wirelumen 34, can be used to transport one or more of a medical device,tools, medicament, or other substance. In some embodiments, the centrallumen 32 is used to transport a prosthetic heart valve. A low-frictionand/or flexible liner 30 can cover the inner surface of the pull-wirelumen 34, and can comprise polytetrafluoroethylene (PTFE),ultra-high-molecular-weight polyethylene (UHMWPE), or another suitablematerial. The liner 30 can be sufficiently flexible and/or distensibleto accommodate insertion of the coil 28 into the pull-wire lumen 34.

As shown in FIG. 3, in the illustrated embodiment, the coil 28 extendsthrough the pull-wire lumen 34 co-axially over the pull wire 22 andterminates short of the steerable distal portion 20 of the shaft. Adistal end portion 44 of the coil can be fixed to the inner liner 30 byany suitable method, such as with a suitable adhesive.

As noted above, a portion of the coil 28 and the pull wire 22 proximatethe handle 12 extend outside of the shaft. Although this portion isillustrated distal from the handle 12 in the illustrated embodiment, inother embodiments, the portion of the coil and pull wire outside of theshaft is enclosed by the handle. The section of the shaft 14 that doesnot contain the coil and the pull wire can be referred to as a “bypassedsegment” 48 of the shaft 14 (FIG. 1). This bypassed segment 48 can havea length L₂ extending from a first location where the coil 28 extendsoutwardly from the shaft 14 at opening 50 to a second location at theproximal end of the coil 28 (at the distal face of the stop member 24 inthe illustrated embodiment). In various embodiments, L₂ can berelatively small in comparison to the length of the shaft 14. In variousembodiments, the overall length of the shaft can be about 91 cm to about152 cm, and the length of the bypassed segment 48 L₂ desirably is in therange of about 5 cm to about 10 cm. In some cases, the ratio of L₂ tothe overall length of the shaft 14 is less than about 1/20, less thanabout 1/15, or less than about 1/10. As can be seen in FIG. 1, thelength Li of the coil 28 extending outside of the shaft is greater thanthe length L₂ of the bypassed segment 48 of the shaft, the significanceof which is explained below. When no tension is being applied to thepull wire 22 and the shaft 14 is in its non-flexed or relaxedconfiguration, the length Li of the portion of the coil 28 extendingoutside of the shaft 14 can be at least about 5-10 mm greater than thelength L₂.

As noted above, the distal end portion 44 of the coil 28 can be fixedrelative to the shaft 14 (FIG. 3) and the proximal end portion 46 can befixed relative to the shaft 14 (via the stop member 24 in theillustrated embodiment in the embodiment illustrated in FIGS. 1 and 1A),while the section of the coil 28 extending outside of the shaftintroduces an amount of slack in the coil. Between the proximal endportion 46 and the distal end portion 44, the coil 28 desirably isunattached or unsecured to the inner surface of the pull-wire lumen 34,the shaft, or any other portion of the delivery device. This allows thecoil to “free float” or freely slide relative to the pull-wire lumen 34,permitting the coil to accommodate relative movement between thepull-wire lumen and the coil as the shaft 14 is advanced through and/orrotated within a tortuous path, for example, when rotated from an insideof a curve to an outside of the curve, without changing the tension onthe pull wire. In this manner, the tensile force of the pull wire 22 canbe transferred to the distal portion 20 of the shaft 14 while the coil28 takes up the tensile force of the pull wire 22 along the proximalportion 18 of the shaft so as to prevent or minimize the application ofa non-concentric tensile force to the proximal portion 18 of the shaft14. Advantageously, this prevents the so-called “whipping” phenomenon ofthe shaft when a torqueing force is applied to shaft, allowing thedistal end of the shaft to be rotated relative to the centrallongitudinal axis to any position through 360 degrees inthree-dimensional space.

Another important advantage of the catheter device 10 is that it onlyrequires a single pull wire to orient the steerable distal portion atany position in three-dimensional space within a body lumen, whereasmany prior art devices utilize multiple pull wires or tensioning membersto effect positioning of the distal portion in more than one flexingplane. As can be appreciated, utilizing only a single pull wire greatlysimplifies the manufacture as well as use of the catheter device.

FIGS. 2A-2D illustrates the use of the catheter device 10 shown inFIG. 1. In FIGS. 2A-2D, the catheter device 10 includes an outer shaft52 that extends over the shaft 14, which is an inner shaft in thisembodiment. The outer shaft 52 can have a pre-set curvature, which inthe illustrated example curves in the x-y plane. Alternatively, theouter shaft 52 can have a steerable distal end portion, the curvature ofwhich can be adjusted using known techniques (e.g., a pull wire andadjustment knob, such as disclosed in any of U.S. Patent ApplicationPublication Nos. 2013/0030519, 2009/0281619, 2008/0065011, and2007/0005131, the disclosures which are incorporated by reference intheir entireties). In cases where the outer shaft 52 is steerable, thehandle 12 can include an additional adjustment knob to control thecurvature of the shaft 52, or a separate handle and respectiveadjustment knob can be provided.

The curvature of the inner shaft 14 can be controlled independently ofthe curvature of the outer shaft 52. Furthermore, the inner shaft 14 canbe freely rotated through 360 degrees relative to the outer shaft 52 (inthe directions indicated by arrows 54, 56) while the both the inner andouter shafts are in their curved or deflected configurations, asillustrated in the drawings. In FIG. 2A, for example, the distal endportion 20 of the inner shaft 14 is curved and lies in the x-y planewith the outer shaft 52, indicating that the inner shaft 14 has not beenrotated or torqued relative to the outer shaft 52 (referred to aszero-degree in-plane flexing). In FIG. 2B, the inner shaft 14 has beenrotated or torqued 90 degrees from the position shown in FIG. 2A so thatthe section of the distal end portion 20 extending from the outer shaft52 lies in the y-z plane while the outer shaft lies in the x-y plane(referred to as 90-degree out-of-plane flexing). In FIG. 2C, the innershaft 14 has been rotated or torqued 180 degrees from the position shownin FIG. 2A so that the section of the distal end portion 20 extendingfrom the outer shaft 52 lies in the x-y plane along with the outer shaft52 (referred to as 180-degree in-plane flexing). In FIG. 2D, the innershaft 14 has been rotated or torqued 270 degrees from the position shownin FIG. 2A so that the section of the distal end portion 20 extendingfrom the outer shaft 52 lies in the y-z plane while the outer shaft liesin the x-y plane (referred to as 270-degree out-of-plane flexing). Ascan be appreciated, the distal end portion 20 of the inner shaft 14 canbe rotated relative to the central axis of the outer shaft 52 to anyrotational position through 360 degrees, with 1:1 correspondence betweenthe handle 12 and distal end portion 20 of the inner shaft 14. Byemploying the pull-wire sleeve 28, the inner shaft 14 can be rotated toany position within the anatomy of a patient and can be maintain thatposition without undesirable whipping. In contrast, using an ordinarysteerable catheter in place of the catheter device 10 as the innercatheter in a coaxial-steerable-catheter arrangement results in a“double banana” configuration, preventing the inner catheter fromrotating relative to the outer catheter without whipping.

It should be noted that the catheter device 10 need not include an outershaft 52. In cases where an outer shaft is not used, component 52 inFIGS. 2A-2D can represent a body vessel (e.g., an artery), which causesthe inner shaft 14 to generally assume the shape of the curved pathwayof the vessel. The delivery device 10 can be operated in the same way asdescribed above such that the inner shaft 14 can be rotated or torquedrelative to its central longitudinal axis to any rotational positionthrough 360 degrees and maintained at that position.

The catheter device 10 can be used to perform any diagnostic,therapeutic, or interventional procedure where access to a targetlocation inside the body of a patient is desired. For example, thecatheter device 10 can be used, for example, to deliver and deploy aprosthetic device in the body, to deliver tools to a target location inthe body, and/or to deliver or introduce drugs or other agents, to namea few exemplary uses. In particular embodiments, the catheter device 10can be a delivery device configured to deliver a prosthetic heart valveto one of the native valves of the heart (the aortic, mitral, pulmonary,or tricuspid valves).

In one specific example, the delivery device can include an inflatableballoon that is configured to expand and deploy a plastically-expandableprosthetic heart valve. The inflatable balloon can be mounted on thedistal end portion of the inner shaft 14, or alternatively, the deliverydevice can include a balloon mounted on a separate shaft that extendsthrough the steerable shaft 14, as further disclosed U.S. PatentApplication Publication Nos. 2013/0030519, 2009/0281619, 2008/0065011,and 2007/0005131, the disclosures of which are incorporated by referencein their entireties. Exemplary plastically-expandable prosthetic heartvalves are disclosed in U.S. Patent Application Publication Nos.2010/0036484 and 2012/0123529, which are incorporated herein byreference.

In another example, the delivery device can be used to delivery anddeploy a self-expandable prosthetic heart valve (e.g., a prostheticvalve having a frame formed from a shape-memory material, such asnitinol). To deliver a self-expandable prosthetic valve, the prostheticvalve can be loaded into a delivery sheath or sleeve in a radiallycompressed state and advanced from the distal open end of the sheath atthe target location to allow the prosthetic valve to expand to itsfunctional size. The delivery sheath can be the distal end portion ofthe steerable shaft 14 or the distal end portion of another shaft thatextends through the steerable shaft 14. Further details regarding aself-expandable prosthetic valve and delivery devices for aself-expandable prosthetic valve are disclosed in U.S. PatentApplication Publication Nos. 2010/0049313 and 2012/0239142, which areincorporated herein by reference.

The delivery device can be introduced and advanced through the patient'svasculature using any known delivery technique. In a transfemoralprocedure, the delivery device can be inserted through a femoral arteryand the aorta to access the heart (typically, but not exclusively usedfor aortic valve replacement). The delivery device is particularlyuseful for delivering a prosthetic valve to the native aortic valve asthe torqueability of the delivery device allows for precise positioningof the prosthetic valve at the target site despite the tortuous pathwaythe delivery device must follow to reach the heart. In atransventricular procedure, the delivery device can be inserted througha surgical incision made on the bare spot on the lower anteriorventricle wall (typically, but not exclusively used for aortic or mitralvalve replacement). In a transatrial procedure, the delivery device canbe inserted through a surgical incision made in the wall of the left orright atrium. In a transaortic procedure, the delivery device can beinserted through a surgical incision made in the ascending aorta andadvanced toward the heart (typically, but not exclusively used foraortic valve replacement). In a transeptal procedure, the deliverydevice can be advanced to the right atrium, such as via a femoral vein,and through the septum separating the right and left ventricles (usedfor aortic or mitral valve replacement).

FIGS. 6 and 7 show a catheter device 100, according to anotherembodiment. The catheter device 100 in the illustrated embodimentcomprises a first pull wire 104, a second pull wire 106, and a shaft 102having a proximal portion 115 (FIG. 8) and a steerable distal portion116. The distal portion 116 can be relatively more flexible than theproximal portion 115, as previously described in connection with thecatheter device 10 of FIG. 1. The proximal portion 115 can be coupled toa handle (not shown) that can have one or more adjustment mechanisms forincreasing and decreasing tension in the pull wires 104, 106. Inparticular embodiments, the catheter device 100 has two adjustmentmechanisms, each of which is connected to a respective pull wire 104,106.

The main body 110 can further comprise a main pull-wire lumen 108extending parallel to a central axis X of the shaft through the proximalportion 115 and through a proximal section 118 of the distal portion116. The main pull-wire lumen 108 can then split into a first distalpull-wire lumen 112 and a second distal pull-wire lumen 114 that divergeaway from each other and then extend generally parallel to each other atangularly spaced locations through a distal section 120 of the distalportion 116 of shaft. The pull wires 104, 106 can thus extend throughthe main pull-wire lumen 108 over the proximal portion 115 and theproximal section 118 of the distal portion 116 of the shaft. The firstand second pull wires 104, 106 then part ways to extend into the firstdistal pull-wire lumen 112 and the second distal pull-wire lumen 114,respectively, over the distal section 120 of the distal portion 116.

FIG. 7 shows the angular positioning of the two distal pull-wire lumens112, 114 (and thus the pull wires 104, 106) along an arc defined by theside wall of the shaft 102. In the illustrated embodiment, the twodistal pull-wire lumens 112, 114 are disposed within the side wall ofthe shaft 102. In other embodiments, the distal pull-wire lumens 112,114 have a different location, for example, adjacent to an interior ofthe side wall or adjacent to an exterior of the side wall. The firstpull-wire lumen 112 can be positioned along a first axis Bi extendingradially from the central axis X of the shaft 102 to the first lumen112. The second pull wire lumen 114 can be positioned along a secondaxis B₂ extending radially from the central axis X of the shaft 102 tothe second lumen 114. As shown, the distal lumens 112, 114 are spacedangularly apart from one another by angle α between axes B₁ and B₂ alongan arc defined by the side wall of the shaft. The angle α can be anyangle greater than zero degrees and less than 180 degrees. In theembodiment shown, the angle α is about 120 degrees. This dual wireconfiguration allows the shaft 102 to have a primary flexing section(corresponding to the proximal section 118 of the steerable distalportion 116) and secondary flexing section (corresponding to the distalsection 120 of the steerable distal portion 116). In some embodiments, adurometer of the primary flexing section 118 is about the same as,higher than, or lower than a durometer of the secondary flexing section120 depending on a desired relative flexibility between the twosections. The primary flexing section has a lower durometer than themain shaft, which is the portion of the shaft 102 proximal of theprimary flexing section in the illustrated embodiment that issubstantially not steerable. In some embodiments, the main shaft has ahigher durometer than the secondary flexing section, which in turn has ahigher durometer than the primary flexing section.

In an alternative embodiment, the pull wires 104, 106 need not extendthrough a common main pull-wire lumen 108 and instead extend throughseparate longitudinally extending pull-wire lumens that are parallel andin close proximity to each other or without any spacing between eachother along the length of the proximal portion 115 and the proximalsection 118 of the distal portion, and then diverge away from each otherand extend along the distal section 120 with a spacing a between the twopull-wire lumens.

When one or both pull wires 104, 106 are under tension, the primaryflexing section 118 flexes or curves in a respective flexing plane P(FIG. 7). By virtue of the pull wires extending through a commonpull-wire lumen (or extending through separate lumens in very closeproximity to each other), tensioning either one or both pull wires iseffective to adjust the curvature of the primary flexing section 118 inits respective flexing plane P. By applying differential tension to thepull wires, the secondary flexing section 120 can be caused to flex invarious different directions relative to the primary flexing section118. For example, applying the same amount of tension to each pull wire104, 106 causes the secondary flexing section 120 to curve in the sameplane P as the primary flexing section. Increasing tension in the firstpull wire 104 relative to the second pull wire 106 causes the secondaryflexing section 120 to curve or bend in a first direction away from theplane P of the primary flexing section 118 (shown in solid lines in FIG.8). Likewise, increased tension in the second pull wire 106 relative tothe first pull wire 104 causes the secondary flexing section 120 tocurve or bend in a second direction, opposite the first direction, awayfrom the plane P of the primary flexing section 118 (shown in phantom inFIG. 8).

In the illustrated embodiment, the secondary flexing section 120 permitsa distal tip of the catheter device 100 to access a locus approximatedby a portion of a surface of a sphere defined by a first range offlexion and a second range of flexion, which in some embodimentscorresponds to the angular components of a spherical coordinate system.The first range has an angular width or azimuthal width a (FIG. 7)(bounded by the radial axes B₁ and B₂). The second range has polar anglewith a minimum at or near the X axis (about 0°) and a maximum dependenton the durometer and length of the secondary flexing section 120(maximally flexed state). Accordingly, tensioning pull wire 104,optionally while partially untensioning pull wire 106, flexes thesecondary flexing section 102 radially outwards generally along axis B₁.Similarly, pull wire 106 is operable to flex the secondary flexingsection 102 along axis B₂. By adjusting the relative tensions betweenthe pull wires 104, 106, the distal tip of the catheter device 100 canbe steered to any intermediate location or point in this space.

The secondary flexing section 120 can thus be made to flex in any radialflexing plane within angle α. The angular positioning of the lumens 112,114 and the pull wires 104, 106 thus defines the azimuthal or firstrange of flexion a for the secondary flexing section 120. In theembodiment shown in, this direction of flexion can be in any planebetween about −60° and about +60° relative to the primary flexing plane,wherein the 0° direction is the primary flexing plane P. Accordingly, inthis case, the first range of flexion α is about 120°. In otherembodiments, the angle a and the corresponding first range of flexioncan vary, such as about 140° (about −70° to about +70°), about 130°(about −65° to about +65°), about 110° (about −55° to about +55°), about100° (about −50° to about +50°), about 90° (about −45° to about +45°),about 80° (about −40° to about +40°), about 70° (about −35° to about+35°), or about 60° (about −30° to about +30°).

In other embodiments, the first range of flexion of the secondaryflexing section 120 need not be symmetrical relative to the primaryflexing plane P. For example, the portion of the first pull wire 104 inthe first distal lumen 112 can be angularly spaced from the main pullwire lumen 108 (and the primary flexing plane P) a first angle θ₁ andthe portion of the second pull wire 106 in the second distal lumen 114can be angularly spaced from the main pull wire lumen 108 (and theprimary flexing plane P) a second angle θ₂, wherein θ₁ and θ₂ are notequal to each other. In this manner, the first range of flexion of thesecondary flexing section 120 encompasses the primary flexing plane Pbut can be adjusted to extend further on one side of the primary flexingplane P than the other.

FIGS. 9, 10, and 11 show a catheter device 200, according to anotherembodiment. The catheter device 200 is similar to the catheter device100 and can have all of the features described above in connection withthe catheter device 100 except that first range of flexion of thesecondary flexing section does not encompass the primary flexingsection. FIG. 9 is a side view, FIG. 10 is a transverse cross-sectionalview, and FIG. 11 is a flattened view with the catheter wall openedalong a line opposite the main pull-wire lumen. Referring to FIGS. 9 and11, the catheter device 200 comprises a shaft 202 having a proximalportion 204 and a distal portion 206. First and second pull wires 208,210, respectively, extend through the proximal and distal portions ofthe shaft. The proximal portion 204 can be coupled to a handle (notshown) that can have one or more adjustment mechanisms for increasingand decreasing tension in the pull wires, either independently ortogether.

The shaft 202 can further comprise a main pull-wire lumen 212 extendingparallel to a central axis X of the shaft through the proximal portion204 and through a proximal section 220 of the distal portion 206. Someembodiments of the shaft include separate pull-wire lumens rather than asingle main pull-wire lumen, as discussed above for the catheter device100. The main pull-wire lumen 212 can then split into a first distalpull-wire lumen 214 and a second distal pull-wire lumen 216 that divergeaway from each other and then extend parallel to each other at angularlyspaced locations through a distal section 222 of the distal portion 206of shaft. The pull wires 208, 210 can thus extend through the mainpull-wire lumen 212 over the proximal portion 204 and the proximalsection 220 of the distal portion 206 of the shaft. The first and secondpull wires 208, 210 then part ways to extend into the first distalpull-wire lumen 214 and the second distal pull-wire lumen 216,respectively, over the distal section 222 of the distal portion 206.Similar to the embodiment of FIGS. 6-7, the proximal section 220 definesa primary flexing section and the distal section 222 defines a secondaryflexing section. The primary flexing section 220 flexes or bends in aprimary flexing plane P.

Unlike the embodiment of FIGS. 6-7, as best seen in FIGS. 9 and 11, atthe distal end of the main pull-wire lumen 212, the distal pull-wirelumens 214, 216 initially extend circumferentially and longitudinallyaway from main pull-wire lumen 212 at different angles or pitches, overa first distance D₁. The distal pull-wire lumens 214, 216 then extendparallel to each other over a distance D₂. Due to the curvatures of thedistal pull-wire lumens 214, 216, the portions of the pull wires 208,210 extending through the distal section 222 are angularly offset to oneside of the primary flexing plane P. The first pull wire 208 isangularly offset from the primary flexing plane P by a first angle α₁and the second pull wire 210 is angularly offset from the primaryflexing plane by a second angle α₂. Thus, the first range of flexion ofthe secondary flexing section 222 is between α₁ and α₂ relative to theprimary flexing plane P. In one specific example, first range of flexionof the secondary flexing section 222 is between +30° and +150° relativeto the primary flexing plane P. However, it should be understood thatthe angles α₁, α₂ can vary in different embodiments wherein α₁ and α₂are any angles between zero and 180 degrees and α₂ is greater than α₁.

In use, tensioning one or both of the pull wires 208, 210 effectivelyadjusts the curvature of the primary flexing section 220 in the primaryflexing plane. By applying different amounts of tension to the pullwires, the secondary flexing section 222 can be made to flex in arespective secondary flexing plane that extends at any angle relative tothe primary flexing plane between α₁ and α₂.

FIG. 12 is a flattened view and FIG. 13 is a transverse cross section ofanother embodiment of a catheter device 300 that is similar to thecatheter devices 100 and 200, and consequently, can include anycombination of features of catheter devices 100 and/or 200. Similarly tothe catheter devices 100 and 200, the catheter device 300 comprises ashaft 302, a proximal portion 204, and a distal portion 206 including aprimary flexing section and a secondary flexing section. A mainpull-wire lumen 312 extends through a wall of the shaft 302 and proximalsection 320 of the distal portion 206, parallel to a central axis X ofthe shaft. A first distal pull-wire lumen 314 a, a second pull-wirelumen 314 b, and a third pull-wire lumen 314 c, diverge from the mainpull-wire lumen before extending longitudinally down a distal section322 of the distal portion 306 of the catheter device.

As shown in FIG. 13, the first pull wire 312 a is offset from theprimary flexing plane P by an angle α₁, the second pull wire 312 b isoffset by α₂, and the third pull wire by α₃, where α₃>α₂>α₁, andα₃<360°. In the illustrated embodiment, the first, second, and thirddistal pull-wire lumens are generally equally spaced around acircumference of the distal section, for example, about 120° apart, andα₁ is about 30°, α2 is about 150°, and α₃ is about 270°. Otherembodiments include other relative spacings and/or offsets for thedistal pull wires and lumens, for example, where control over aparticular part of a total accessible range of secondary flexing portionis of greater interest to a user.

The first, second, and third pull-wire lumens 314 a, 314 b, and 314 cextend distally from the main pull-wire lumen and divergecircumferentially from each other over a distance D₁, then continuedistally, generally parallel to each other over a distance D₂. In theillustrated embodiment, the first distal pull-wire lumen 314 a extendsfrom the main pull-wire lumen at an angle, but in other embodiments, thefirst pull-wire lumen extends substantially straight out of the mainpull-wire lumen.

The catheter device also includes a first pull wire 308 a, a second pullwire 308 b, and a third pull wire 308 c. The pull wires 308 a, 308 b,and 308 c are disposed within the main pull-wire lumen 312, and withintheir respective distal pull-wire lumens 314 a, 314 b 314 c. A distalend of each pull wire is secured to the wall of the catheter device ator near a distal end 324 thereof, for example, terminating at a ring ator near the distal end 324. In other embodiments, the distal ends of thepull wires are secured to the wall at a location more proximal than thedistal end 324, for example, in embodiments in which the distal end 324is not steerable. The proximal section 320 of the distal portion definesa primary flexing section, and the distal section 222 defines asecondary flexing section, which is generally coextensive with the partof the shaft 304 housing the distal pull-wire lumens in the illustratedembodiment.

As such, the illustrated embodiment of catheter device 300 is similar tothe illustrated embodiment of catheter device 200 with the first andsecond pull wires 308 a, 308 b corresponding to the first and secondpull wires 208, 210, respectively, and the first and second distalpull-wire lumens 314 a, 314 b corresponding to the first and secondpull-wire lumens 214, 216, respectively. The catheter device 300 alsoincludes the third pull wire 308 c and respective third pull-wire lumen314 c, the addition of which, in combination with the first and secondpull wires, increases a first range of flexion of the secondary flexingportion to a full 360° around the central axis X in the illustratedembodiment.

As discussed above, some embodiments of the catheter device 300 have adifferent configuration of the pull wires, for example, unequalcircumferential spacing. Some of those configurations will not have aneffective first range of flexion of 360° around the axis X, but insteadwill have a reduced effective first range of flexion, for example, about240°, or about 180°.

In general, deflecting the second flexing section is more controllablewhen the pair of pull wires controlling that portion of the deflectionare disposed closer together circumferentially (e.g., a smaller angularwidth). As such, there is a tradeoff between controllability and range.Accordingly, some embodiments of the catheter device 300 include greaterthan 3 pull wires, embodiments of which provide improved controllabilityin combination with up to a 360° first range of flexion.

General Considerations

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein. Thedisclosed methods, devices, and systems should not be construed aslimiting in any way. Instead, the present disclosure is directed towardall novel and nonobvious features and aspects of the various disclosedembodiments, alone and in various combinations and sub-combinations withone another. The methods, devices, and systems are not limited to anyspecific aspect or feature or combination thereof, nor do the disclosedembodiments require that any one or more specific advantages be presentor problems be solved.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, it shouldbe understood that this manner of description encompasses rearrangement,unless a particular ordering is required by specific language. Forexample, operations described sequentially may in some cases berearranged or performed concurrently. Moreover, for the sake ofsimplicity, the attached figures may not show the various ways in whichthe disclosed methods can be used in conjunction with other methods. Asused herein, the terms “a”, “an”, and “at least one” encompass one ormore of the specified element. That is, if two of a particular elementare present, one of these elements is also present and thus “an” elementis present. The terms “a plurality of” and “plural” mean two or more ofthe specified element.

As used herein, the term “and/or” used between the last two of a list ofelements means any one or more of the listed elements. For example, thephrase “A, B, and/or C” means “A”, “B”, “C”, “A and B”, “A and C”, “Band C”, or “A, B, and C.”

As used herein, the term “coupled” generally means physically coupled orlinked and does not exclude the presence of intermediate elementsbetween the coupled items absent specific contrary language.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A steerable catheter device, comprising: a shaft comprisinga proximal portion, a distal portion, and a pull-wire lumen that extendsat least partially through the proximal and distal portions; a pull wireextending through the pull-wire lumen and having a proximal end portionand a distal end portion, wherein the distal end portion of pull wire isfixed to the distal portion of the shaft; an adjustment mechanismoperatively connected to the proximal end portion of the pull wire andconfigured to increase and decrease tension in the pull wire to adjustthe curvature of the distal portion of the shaft; and an axiallynon-compressible pull-wire sleeve extending co-axially through thepull-wire lumen and over the pull wire.
 2. The catheter device of claim1, wherein the pull-wire sleeve comprises a closed-pitch coil.
 3. Thecatheter device of claim 1, wherein the pull-wire sleeve isfree-floating within the pull-wire lumen.
 4. The catheter device ofclaim 1, wherein the pull-wire sleeve comprises a proximal end portionthat extends outside of and alongside the shaft and the pull wireextends proximally past the proximal end portion of the pull-wiresleeve.
 5. The catheter device of claim 4, further comprising a handleand a stop member fixed relative to the shaft at a location distal tothe handle, and wherein the pull-wire sleeve has a proximal terminal endfixed to the stop member, and the pull wire extends proximally throughthe stop member and into the handle.
 6. The catheter device of claim 4,wherein the proximal end portion of the pull-wire sleeve extendingoutside of the shaft is longer than a section of the shaft measured froma first location where the pull-wire sleeve first extends outside of theshaft to a second location at a proximal terminal end of the pull-wiresleeve.
 7. The catheter device of claim 1, wherein the pull-wire sleevecomprises a distal terminal end that is fixed relative to the shaftinside of the pull-wire lumen and a proximal terminal end that is fixedrelative to the shaft, and the pull-wire sleeve is unattached to thepull-wire lumen between the distal terminal end and the proximalterminal end.
 8. The catheter device of claim 1, wherein the pull wireextends distally past the pull-wire sleeve into a distal section of thepull-wire lumen not occupied by the pull-wire sleeve.
 9. The catheterdevice of claim 1, wherein the shaft comprises a first shaft and thecatheter device further comprises a second shaft and another adjustmentmechanism configured to adjust the curvature of a distal portion of thesecond shaft, the first shaft extending co-axially through and distallypast the second shaft such that the curvature of the distal portion ofthe first shaft can be adjusted relative to the second shaft.
 10. Thecatheter device of claim 1 consisting of only one pull wire.
 11. Amethod comprising: providing a catheter device having a shaft, a pullwire extending through the shaft, and an axially non-compressiblepull-wire sleeve, the pull wire extending at least partially through thepull-wire sleeve, the pull wire and the pull-wire sleeve being radiallyoffset from a central axis of the shaft, wherein the shaft comprises aproximal portion and a distal portion; inserting the catheter deviceinto the body of a patient; and applying tension to the pull wire toadjust the curvature of the distal portion of the shaft.
 12. The methodof claim 11, further comprising torqueing the shaft to rotate the distalportion of the shaft after inserting the catheter device into the bodyand adjusting the curvature of the distal portion of the shaft.
 13. Themethod of claim 11, further comprising mounting a prosthetic valve in aradially compressed state on the catheter device, inserting theprosthetic valve into the body of the patient when inserting thecatheter device into the body, and deploying the prosthetic valve withinthe body.
 14. The method of claim 11, wherein applying tension to thepull wire to adjust the curvature of the distal portion of the shaftcauses the pull-wire sleeve to move axially relative to the shaft. 15.The method of claim 11, wherein the pull-wire sleeve comprises aproximal end portion that extends outside of and alongside the shaft andthe pull wire extends proximally past the proximal end portion of thepull-wire sleeve.
 16. A steerable catheter device, comprising: a shafthaving a proximal portion and a distal portion; and first and secondpull wires having respective proximal portions and respective distalportions, the proximal portions of the first and second pull wiresextending through the proximal portion of the shaft in close proximityto each other, and the distal end portions of the first and second pullwires extending through the distal portion of the shaft in closeproximity to each other over a first distance defining a primary flexingsection, diverging away from each other over a second distance, and thenextending parallel to each other at angularly spaced locations over athird distance defining a secondary flexing section; wherein tensionapplied to the first pull wire and/or the second pull wire is effectiveto flex the distal portion away from the central axis of the shaft,wherein the direction of flexion is determined by the relative tensionsin the pull wires.
 17. The catheter device of claim 16, wherein theshaft comprising a main pull-wire lumen extending through the proximalportion of the shaft and first and second distal pull-wire lumensextending from the main pull-wire lumen, the distal pull-wire lumensdiverging away from each other and then extending parallel to each otherat angularly spaced locations toward a distal end of the shaft, thefirst pull wire extending through the main pull-wire lumen and the firstdistal pull-wire lumen, and the second pull wire extending through themain pull-wire lumen and the second distal pull-wire lumen.
 18. Thecatheter device of claim 16, wherein the distal portions of the firstand second pull wires are angularly spaced apart from each other at anangle of less than 180 degrees.
 19. The catheter device of claim 16,wherein the distal portions of the first and second pull wires areangularly spaced apart from each other at an angle of about 120 degrees.20. The catheter device of claim 16, wherein the range of flexion of thedistal portion of the shaft is equal to the angular spacing between thefirst and second pull wires.
 21. The catheter device of claim 16,wherein the first and second pull wires are configured such that whenincreased tension is placed on the first pull wire, relative to tensionplaced on the second pull wire, the curvature of the primary flexingsection is adjusted in a first plane and the curvature of the secondaryflexing section is adjusted to extend away from the first plane.